The present invention relates generally to an infrared laser battlefield identification beacon, and more particularly to an Identification Friend or Foe (IFF) system using a CO.sub.2 identification beacon on a ground vehicle such as a tank, in conjunction with an existing Forward Looking InfraRed (FLIR) detection system on an aircraft or on another ground vehicle.
The Desert Storm conflict in the Persian Gulf in early 1991 has highlighted the need to identify friendly targets on the battlefield. This identification capability is difficult to achieve because of the complexity of the problem, the large number of vehicles involved, and the resulting high cost. Today's technology allows targeting a ground vehicle well before positive visual identification can be made. Night operations have increased the reliance on sensors that have lower resolution than daytime visual optics, and "smart" weapons and weapon systems have greatly increased the effectiveness of our forces. The rapidity of battle with current systems and tactics makes the task of identification by a forward observer more difficult than in the past.
Another factor of modern warfare that became apparent during Desert Storm is the intermixing of typically "enemy" and "friendly" vehicle types on both sides of the conflict. The combination of international arms sales and changing political alliances along with the use of a coalition force structure have made confirmation of friend or foe impossible to guarantee--even from within visual range. As a result, current identification of forces is highly dependent on knowledge of position.
U.S. air forces already have a somewhat effective solution for identifying friendly targets in the air-to-air and ground-to-air arenas for at least two reasons. First, the nature of air combat requires long-range weaponry which makes the identification problem critical for antiair targeting. Second, the cost of airborne platforms has generally been sufficiently high to justify the additional expense of incorporating "Identification Friend or Foe" (IFF) systems on such platforms in order to minimize loss of valuable assets.
Ground forces have historically operated at a much slower pace, they attacked from a relatively close range, and the cost of their vehicles (until recently) has been relatively low. These factors, along with technical difficulties, have hindered the development of a fully effective identification system for air-to-ground and ground-to-ground combat. The recent incidents of fratricide, however, demand that solutions be provided to the identification problem.
The properties of any ID device need to be evaluated in relation to their effect on the following five factors:
(1) Observability: The device should not significantly increase the observability of our forces by enemy systems;
(2) Detectability: If the ID function of the device is detectable by the enemy, the enemy may be able to use it for ID as well;
(3) Exploitability: If the enemy can detect the ID function or determine or estimate its nature through intelligence methods, he may find a way to counter the system or to imitate its function;
(4) Reliability: Whatever system is considered, it must be able to provide reliable ID information to achieve minimum error in identifying friendly assets; and
(5) Compatibility: Unless a separate ID system is added to the attacking aircraft or ground vehicle, ID devices will have to be compatible with existing weapon system capabilities.
An implied requirement of any ID system is its ability to perform in a method or tactic that is workable in modern warfare. Preferably, the ID system should function without increasing the operator's work load, without increasing vulnerability and without lowering effectiveness.
The following U.S. Pat. Nos. are of interest.
5,142,288 - Cleveland
5,073,780 - Barley et al
5,001,488 - Joguet
4,995,101 - Titterton et al
4,837,575 - Conner, Jr.
4,814,769 - Robin et al
4,685,800 - Paquet
4,477,796 - Kearsley
4,277,170 - Miles
The patent to Conner, Jr, discloses a secure identification system which produces two interrogation pulses aimed at the target and separated from each other by a random time. The target detects the two interrogation pulses and prepares a reply signal which is controlled by the elapsed time. The patent to Cleveland discloses returning the same signature message as received, but is delayed by a predetermined time interval. The patents to Joguet, Barley et al, and Robin et al disclose friend-foe identification systems. The patent to Titterton et al discloses secure submarine communication. The patents to Paquet, Kearsley and Miles are of less interest.